#define _CRT_SECURE_NO_WARNINGS 

#include"string.h"

namespace xsc
{
	const size_t string::npos = -1;

	void string::reserve(size_t n)
	{
		if (n > _capacity)
		{
			char* tmp = new char[n + 1];
			_capacity = n;
			strcpy(tmp, _str);
			delete[] _str;
			_str = tmp;
		}
	}

	void string::push_back(char ch)
	{
		if (_size == _capacity)
		{
			reserve(_capacity == 0 ? 4 : 2 * _capacity);
		}

		_str[_size] = ch;
		++_size;
		_str[_size] = '\0';
	}

	void string::append(const char* s)
	{
		size_t len = strlen(s);

		if (len + _size > _capacity)
		{
			reserve(len + _size > 2 * _capacity ? len + _size : 2 * _capacity);
		}
		strcpy(_str + _size, s);
		_size += len;
	}

	string& string::operator+=(char ch)
	{
		push_back(ch);

		return *this;
	}

	string& string::operator+=(const char* s)
	{
		append(s);

		return *this;
	}

	void string::insert(size_t pos, char ch)
	{
		assert(pos <= _size);

		if (_size == _capacity)
		{
			reserve(_capacity == 0 ? 4 : 2 * _capacity);
		}
		size_t end = _size + 1;
		while (end >= pos + 1)
		{
			_str[end] = _str[end - 1];
			--end;
		}

		_str[pos] = ch;
		++_size;
	}

	void string::insert(size_t pos, const char* s)
	{
		assert(pos <= _size);

		size_t len = strlen(s);

		if (len + _size > _capacity)
		{
			reserve(len + _size > 2 * _capacity ? len + _size : 2 * _capacity);
		}

		size_t end = _size + len;
		while (end >= pos + len)
		{
			_str[end] = _str[end - len];
			--end;
		}

		size_t i = 0;
		for (; i < len; i++)
		{
			_str[pos + i] = s[i];
		}

		_size += len;
	}

	void string::erase(size_t pos, size_t len)
	{
		assert(pos < _size);

		if (len > _size - pos)
		{
			_str[pos] = '\0';
		}
		else
		{
			size_t i = pos + len;
			for (; i <= _size; ++i)
			{
				_str[i - len] = _str[i];
			}
		}
		
		_size -= len;
	}

	size_t string::find(char ch, size_t pos)
	{
		assert(pos < _size);

		size_t i = pos;
		for (; i < _size; ++i)
		{
			if (_str[i] == ch)
			{
				return i;
			}
		}
		
		return -1;
	}

	size_t string::find(const char* s, size_t pos)
	{
		assert(pos < _size);

		char* tmp = strstr(_str + pos, s);
		if (tmp == nullptr)
		{
			return -1;
		}
		return tmp - _str;
	}

	string string::substr(size_t pos, size_t len)
	{
		string ans;

		if (len > _size - pos)
		{
			len = _size - pos;
		}

		ans.reserve(len);

		size_t i = 0;
		for (; i < len; i++)
		{
			ans += _str[i+pos];
		}

		return ans;
	}

	bool operator<(const string& s1, const string& s2)
	{
		return strcmp(s1.c_str(), s2.c_str()) < 0;
	}

	bool operator<=(const string& s1, const string& s2)
	{
		return s1 < s2 || s1 == s2;
	}

	bool operator>(const string& s1, const string& s2)
	{
		return !(s1 <= s2);
	}

	bool operator>=(const string& s1, const string& s2)
	{
		return !(s1 < s2);
	}

	bool operator==(const string& s1, const string& s2)
	{
		return strcmp(s1.c_str(), s2.c_str()) == 0;
	}

	bool operator!=(const string& s1, const string& s2)
	{
		return !(s1 == s2);
	}

	ostream& operator<<(ostream& out, const string& s)
	{
		for (auto ch : s)
		{
			out << ch;
		}

		return out;
	}

	istream& operator>>(istream& in, string& s)
	{
		s.clear();

		const int N = 256;
		char buff[N];
		int i = 0;

		char ch;
		//in >> ch;
		ch = in.get();
		while (ch != ' ' && ch != '\n')
		{
			buff[i++] = ch;
			if (i == N - 1)
			{
				buff[i] = '\0';
				s += buff;

				i = 0;
			}

			//in >> ch;
			ch = in.get();
		}

		if (i > 0)
		{
			buff[i] = '\0';
			s += buff;
		}

		return in;
	}
}